A 32-year-old woman from Delhi underwent evacuation of a complete hydatidiform mole 8 weeks ago. She was counseled about contraception and close follow-up. Today, she presents with persistent vaginal bleeding and lower abdominal pain. Her serum β-hCG, which had declined to undetectable levels 2 weeks post-evacuation, is now 15,000 mIU/mL. Pelvic ultrasound shows a heterogeneous mass in the uterine cavity with abnormal vascularity on Doppler. There is no evidence of metastatic disease on chest X-ray or abdominal imaging. What is the most appropriate next step in management?

Explanation

## Diagnosis and Management: Invasive Mole (Low-Risk GTN) ### Clinical Diagnosis **Key Point:** The rising β-hCG after initial decline to undetectable levels, combined with a heterogeneous intrauterine mass on ultrasound, is diagnostic of invasive mole (a form of gestational trophoblastic neoplasia). The absence of metastatic disease on staging imaging indicates low-risk GTN. ### Diagnostic Criteria for Invasive Mole | Criterion | Finding in This Case | |-----------|----------------------| | **β-hCG pattern** | Plateau or rise after initial decline | | **Ultrasound** | Heterogeneous mass with abnormal vascularity | | **Myometrial invasion** | Suggested by Doppler abnormality | | **Metastases** | Absent (chest X-ray, abdominal imaging negative) | | **Histology** | Trophoblastic tissue invading myometrium (if biopsy done) | **High-Yield:** Invasive mole is defined by persistent/rising β-hCG AND imaging evidence of intrauterine disease (usually myometrial invasion) WITHOUT metastases. It is a form of low-risk GTN. ### WHO Risk Scoring for GTN **Key Point:** GTN is stratified into low-risk and high-risk disease based on prognostic factors: **Low-Risk GTN:** - β-hCG <1,000 or 1,000–10,000 (depending on score) - Duration of disease <4 months - No metastases or only lung metastases - No prior chemotherapy - Score <7 **High-Risk GTN:** - β-hCG >100,000 - Duration >4 months - Brain or liver metastases - Prior chemotherapy failure - Score ≥7 This patient has β-hCG 15,000, no metastases, and recent onset — **low-risk GTN**. ### Treatment Algorithm for Low-Risk GTN ```mermaid flowchart TD A[Low-Risk GTN Diagnosed]:::outcome --> B{Desires Fertility?}:::decision B -->|Yes| C[Methotrexate Monotherapy]:::action B -->|No| D[Hysterectomy + Chemotherapy]:::action C --> E[Weekly MTX until β-hCG undetectable]:::action E --> F[Continue 1-2 cycles post-normalization]:::action F --> G[Serial β-hCG for 12 months]:::action D --> H[Chemotherapy for 3-6 months]:::action H --> I[Serial β-hCG for 12 months]:::outcome ``` **Clinical Pearl:** In a young woman (age 32) who may desire future fertility, chemotherapy alone is preferred over hysterectomy. Repeat evacuation is NOT indicated because the diagnosis is invasive mole (myometrial invasion), not residual molar tissue in the cavity. ### Chemotherapy Regimen for Low-Risk GTN **Key Point:** Methotrexate monotherapy is the first-line agent for low-risk GTN: **Methotrexate Dosing:** - **Weekly regimen:** 30 mg/m² IV or IM once weekly - **5-day regimen:** 1 mg/kg/day × 5 days, repeated every 14 days - Continue until β-hCG becomes undetectable - Then give 1–2 additional cycles for consolidation - Cure rate: >95% with methotrexate monotherapy in low-risk disease **Monitoring:** - β-hCG weekly during treatment - CBC, liver function, renal function before each cycle - Contraception mandatory during and for 3 months after chemotherapy **Warning:** Do NOT use repeat evacuation as primary treatment for invasive mole — the disease has invaded the myometrium and will not be removed by curettage alone. ### Why Other Options Are Incorrect 1. **Repeat evacuation + methotrexate:** Repeat evacuation is not indicated for invasive mole because the trophoblastic tissue has invaded the myometrium, not just the cavity. Methotrexate alone is sufficient for low-risk disease in a fertility-desiring woman. 2. **Hysterectomy:** While hysterectomy can be offered to women who have completed childbearing, it is NOT the first-line treatment for low-risk GTN in a young woman. Chemotherapy alone has >95% cure rate and preserves fertility. 3. **Observation:** Observation is contraindicated in invasive mole because the disease will progress without chemotherapy. Rising β-hCG indicates active disease.